<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>镂空遮罩</title>
    <link rel="stylesheet" href="./index.css">
</head>
<body>
    <!-- 遮罩层的限制层：overflow：hidden控制不出现滚动条 -->
    <div class="test_outer">
        <!-- 遮罩层 -->
        <span id="testCover" class="test_cover test_cover_pos1 trans"></span>
    </div>
</body>
</html>